ok i have a small practice type amp its a marshall 10w maybe i dont remeber i got it used but i was lookin at some amps online today some have a head what is that exactly? and i do plan to step up to a larger one im not even talkin a half stack but a little more power would be nice i was just starting my research now... also what is a tube amp? i read some quick things im just curious as to the difference in sound..
Jerm
An amplifier consists of three general parts:
1) The preamp. Here the sound is shaped most, with EQ knobs, gain etc.
2) The power-amp. Here the sound from the pre-amp is amplified to proper volume levels. Transistor poweramps tend to leave the pre-amp sound intact. Tube poweramps will tend to colour the sound the more you drive them.
3) Speaker(s). The signal from the poweramp goes to the speaker from which the actual sounds come.
Your Marshall is a combo, all parts are in one convenient package. A head is only the pre-amp and poweramp combined, you'll need speakers attached to it to have them work. A half stack therefor consists of a top-unit and a speaker cabinet.
You also have three general types of amps:
1) Tube amps. The oldest kind of amp, uses tubes (or valves). The sound changes depending on how hard you make them tubes 'work'. So 'cranking' a tube amp refers to having the tubes 'work' very hard, creating a natural overdrive. These kinds of amps are what you hear on most records. Currently the Epiphone Valve Junior seems to be the hype on GN, you have the head for $100 and the combo for $160.
2) Transistor/Solid State amps. Appearing a few decades ago these were once designed to make tube amps obsolete. Cheaper, more consistent and lighter weight these amps were the future. Unfortunately it turned out that transistors do not overdrive the same as tubes do and many people prefer the sound of tube amps. Some SS amps have made their way into the history books though. For example the Roland Jazz-Chorus 120 has been a favourite with jazz players for it's ultra clean sound.
3) Digital amps. A subdivision of SS amps, digital amps have a Digital Signal Processor (DSP-chip) that changes the sound. Usually this is done to imitate expensive tube amps although the technical possibilities go way beyond that. How well this sound depends a lot on how the DSP-chip works, digital (modeling) amps cost between $70 and $2000. A curious side-effect of using DSP-chips is that, just as with computers, your amp tends to be obsolete after a few years, when better, more accurate amp simulations hit the market. The 'tube vs digital' discussion is fought out on every guitar forum atleast once every year and the end is not in sight.
